1.KAT7 promotes chondrocyte senescence by activating the PI3K/AKT/mTOR signaling pathway
Kang Wang ; Ying Li ; Nuo Xu ; Tingting Guo ; Yun Chen ; Xuran Zeng ; Liqi Sun ; Haochen Xu ; Wei Wei ; Shangxue Yan
Acta Universitatis Medicinalis Anhui 2025;60(8):1506-1513
Objective :
To establish an interleukin-1β (Il-1β) induced inflammatory model of rat articular chondro- cytes (ACs) , and to investigate the relationship between the expression of lysine acetyltransferase 7 (KAT7) under inflammatory stimulation and the senescence of ACs.
Methods:
Primary ACs were obtained by digestion of rat knee cartilage with collagenase type Ⅱ and identified. The inflammatory model of ACs was induced by IL-1β . KAT7 was over-expressed or knocked down in ACs by adeno-associated virus infection or small interfering RNA transfection , respectively. A negative control group was set up. Transwell assay was used to detect cell migration ability. Senes- cent cells were stained with senescence-associated β-galactosidase (SA-β-Gal) . Western blot ( WB) was used to detect the protein expression levels of KAT7 , collagen type II (Col Ⅱ ) , matrix metalloproteinase 13 (MMP13) , tumor protein p53 (p53) and cyclin-dependent kinase inhibitor 1A (p21) . The cells of negative control group and KAT7 over-expression group were performed for RNA sequencing , and WB was used to verify the related signaling pathways obtained by Kyoto encyclopedia of genes and genomes (KEGG) enrichment analysis.
Results:
Compared with the control group , the SA-β-Gal staining was enhanced , the protein expression of Col Ⅱ decreased , the pro- tein expression of MMP13 and p53 increased , the cell migration ability decreased , and the expression of KAT7 also increased in the ACs of rats after IL-1β stimulation. Compared with the negative control group , the SA-β-Gal stai- ning was enhanced , the protein expression of Col Ⅱ decreased , the protein expression of MMP13 , p53 and p21 in- creased , and the cell migration ability decreased in the KAT7 over-expression group. Compared with the negative control group , the SA-β-Gal staining was weakened , the protein expression of Col Ⅱ increased , the protein expres- sion of MMP13 , p53 and p21 decreased , and the cell migration ability was enhanced in the KAT7 knockdown inflammatory model of ACs. KEGG enrichment analysis showed that phosphatidylinositol 3-kinase/protein kinase B (PI3K/AKT) signaling pathway was activated. Compared with the negative control group , the relative protein ex⁃pression levels of phosphorylated protein kinase B (p⁃AKT)/AKT and phosphorylated mammalian target of rapamy⁃cin (p⁃mTOR)/mTOR in KAT7 over⁃expression group increased. The relative protein expression levels of p ⁃AKT/AKT and p ⁃mTOR/mTOR in KAT7 knockdown cells decreased.
Conclusion
Rat ACs with high expression of KAT7 exhibit senescence and osteoarthritis phenotype , and the mechanism may be related to the activation of PI3K/AKT/mTOR signaling pathway by KAT7.


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